The social network, Friends Reunited, is set to close after 15 years of being online.
Steve Pankhurst, one of the site's early founders, said in an email that the site was "no longer used for the purpose it was built for".
In the wake of the announcement, he appeared to be surprised over Twitter's interest as the topic started trending.
I am honestly surprised people are still interested - I've got FR trending on Twitter— Steve Pankhurst (@spankyhurst) January 18, 2016
According to PA, Pankhurst said: "I knew it was near impossible to reboot something that was old and in decline."
Launching in 2000, it was bought by ITV for £175million five years later. Despite racking up more than 10 million registered users, the network failed to keep up with new social media sites such as Facebook and Twitter.
"And I also realised that of the more than 10m users registered, a lot had done so over a decade ago and hence their contact details were out of date," Pankhurst wrote.
Those who remembered Friends Reunited tweeted their surprise over how long it has taken for the site to close.
Others took the opportunity to bid farewell while few questioned whether the same demise would follow similar networking sites.
Friends Reunited closing down gives me hope that LinkedIn's days are numbered and my inbox's spam filter will finally get a day off.— mchawk (@mchawk) January 18, 2016
Friends Reunited is closing?
OH MY GOD... How's Tom on Myspace taking the news?!— Ben (@0point5twins) January 18, 2016
Sad to hear about Friends Reunited closing. First time I had heard of social media was my Mum signing up & making lots of new-old friends!— Alex Gillham (@AlexKGillham) January 18, 2016
Friends Reunited is shutting down. In other news, the quill is being phased out as a writing implement— Robert Rea (@robertrea) January 18, 2016